Rotary steam engine



A. D. lsKoLs ROTARY STEAM ENGINE 1 June 27, 1944.

Filed Aug. 14, 1941 2 Sheets-Sheet l .a. 19mm June 27, 1944. A. D. ISKOLS ROTARY STEAM ENGINE 2 Sheets-Sheet 2 Filed Aug. 14, 1941 Patented June 27, 1944 UNITED STATES PATENT OFFICE 2,352,544 ROTARY sT mMENGiN Anatol David Iskols, Bronx, N. Y. Application August 14, 1941, Serial Ne. 406,827 6 Claims. (01. 121578) My invention relates to improvements in rotary steam engines and the object is to provide asimple, rugged and easily maneuverable engine for use in ship propulsion.

In modern steamships the propeller is driven either by a reciprocating steam engine or by a steam turbine. Although these two types of steam engines have been developed to a high degree of perfection still both have inherently some unfavorable features which cannot be eliminated. Thus, the reciprocating engine requires the rather complicated crank mechanism in order to transform the straight motion of the piston into the rotating motion of the main shaft. This means, especially in triple or quadruple expansion engines, a great number of moving and working parts resulting in structure taking up much valuable space in length and height besides making it very heavy and costly to produce.

The steam turbine requires for its emciency a very high speed of rotation while the propeller, just in the opposite, is more efiicient at a relatively low speed of rotation; therefore, a reducing mechanism must be introduced between the turbine and propeller. Further, the steam turbine not being reversible requires an additional reverse turbine running idle when the s ip is go ng ahead which is practically all the time; and many other such features.

In my improved rotary steam engine, as will be shown, the favorable features of both the above types of steam engines are retained while the unfavorable ones are practically eliminated, resuling in a very simple, compact, easy to manufacture engine with a great reduction ,in spa e. weight and cost.

How these results are attained is described in the following specification with reference to te annexed drawings in which:

Fig. l is a cross section of my rotary steam encfne substantially on line AA of Fig. 2.

Fig. 2 is a longitudinal section. and view partly. in elevation. i

Fig. 3 is a view on line BB of Fig. 2 showing the operating mechanismof the roller gate.

Fig. 4 is a front view specifically showing the operating mechanism of the steam admitting and cutting ofi valve.

5 is a detail.

Fig. 6 is a cross section of my rotary with a double piston rotor.

Fig. '7 is an outline sketch of a compound rotary steam engine.

' Figs. 8 and -9 are details of elements preventing steam leakage,

Fig. 10 shows diagrammatically the different phases of the workingfcy cle.

My improved rotary steam engine belongs to the piston type rotaries and has as shownin Figs. 1 and 2 bolted to bedplate I the ,main cylinder .2 being. preferably cast at both ends open and provided .with flanges to which are bolted the .end covers-3, 4. Main-shafticci: axial with cylinder-2, penetrates both end covers 3, 4 through suitable stufiing boxes and is supported by bearings 6, I mounted on bedplate l and adjustable horizontally and vertically to in.- sure true coaxiality of main shaft 5 with cylinder 2. v

Main shaft- 5 carries fixedly mountedon it and extending the full. length'of the inner cylindrical space between-end covers 3, 4 a runner or rotor consisting of two parts: a relatively large cylindrical hub 8 coaxial with the main shaft and a piston 9 projecting radially from hub 8 to the inner surface of cylinder 2 and running in they concentric annular space between hub 8 and cylinder 2.

A blister ID of cylindrical shape whose axis is parallel with the. axis of cylinder is cast integral with, extends the full length of. cylinder v 2 and is opening into the annular space.- Thisblister being also open on both ends is closed by extensions of end covers ,3, 4 and houses coaxially with it a roller gate ll serving as an abutment which reaches hub 8 of the rotor and being rotatable can open andclose the annular. space as needed. Gate l-lis fixedly mounted on. shaft l2 which is coaxial with blister lll pene; trating-both end covers through suitable stuff ing boxes-and is supported by adjustable. bearings I3 in brackets -l4.f One end of shaft [2. carries keyed to it arm l5 having a pinjournaled in one end of spring IS the other end ofwhich is pivoted on post ll.v Spring. It being in tension tends to bring arm l5 into a vertical or neutral position and with it gate H into ahorizontal which is its neutral position asshow'n in Fig. 1091.

On top of blister I0 is bolted to it steamuchest l8 receiving steam from the boiler through pipe I9, nozzle 20 and. containingpoppetvalve' 21' which is lifted by forked arm 22 keyed on; shaft,

23, while spring 24 brings the valve down, on its seat and .closes it. The spindle of\valve; 2l may be connected to a dashpot 25 ofconventional 'type to reduce the; shock in seatingthe Valve. Shaft 23 whose one end ,t,J'QI1rnaled=on steam chest I8 is extended to the front, supported by bracket 26 and is carrying keyed to it the operating arm 21.

As shown in Figs. 1 and a when poppet valve 2| is open the admission steam flows through inlet port 28 in blister l0, passage 29 in gate into the annular space in front of piston 9 causing the rotor to run in the direction of the arrow. At a certain predetermined point of the rotation of piston 9 valve 2| is seated, the steam admission is cut ofi, the steam enclosed between the then stationary gate II and the moving ahead piston 9 as shown in Fig. 10b is expanding until the piston arrives to the position shown in Fig. 100 and is beginning to open the annular space containing the expanded steam to the exhaust. At this point gate.

also begins to rotate to its neutral position of Fig. 10d permitting the free passage of piston 9.. soon as the pistonclears the gate the latter is made to snap back into its closed and stationary positionFigs. 1 andlOa and the new Working cycle is repeated. 7

intermittentand periodic movement of gate is produced by the? following operating meplf anism.. For goin'gr ahead there .is mounted fixedly .onmain shaft. 5 disk 30 having a notch 3|, Bell crank}; pivoted inbracket 33 on bedplate carries on one .end a roller 34 which follows the contour of 'disk 31] while the other end is connectedby toggle link 35 toarm 36 which can engage arm |5.keyedon shait|2 which latter operatesgate ll Arm l5 which isflxedly keyed .to shaft i2 has, as shown in Fig. 5, on one side of its hub a male jaw 31 forming. apartial clutch, by being in contact on one side n wit a si e ma w ..h Ofarm 3.6. whi h latter. slq se pivot d .15m "1 and prevented .from spreading. by a standard c lar-.19

wh nshownxoajith i s d n 3 toggle link 35 is set then arm I5, arm 36, toggle 35 nd.b.e :anl ...3 j 9rm a -q sed in system whose movement iscontroiledon one. side by disk 30. and on. the other sieebx '5- 501mg r ller. .4 lo sthe i 's ar'p h ry oidi 30 .this link system. and gate remain stationary in .the position shown in Figs. l 3 and 10a ,b. that. is, gate keeps the annular space between itand the. piston closed. However, when notch 3| arrives opposite roller 334 spring |6 being in tension .can pull arm lfi into its vertical position and turn with it gate intoits horizontal .or neutral position ot Fig'. -'10 d giving" piston S free passage." In further rotation notch 3| of disk ,30 passes roller 34 the latter is pushed out by the disk periphery bringing the Iinksystenifagaininthe position: of Fig. 3and-the gate intoits closed positionfjig. 1;

,And so with each revolution'of the engine this it is immediately exhausted or its pressure equalized on both sides of the piston.

When the rotation of the engine is reversed then disk 39 with a suitablenotch, bell crank 40 pivoted in a bracket similar to 33 and carrying roller 4|, toggle link 42 which is now set and arm 43 come into play, the gate having been reversed, that is, brought into the position of Fig. 10c which is to the other hand of the one shown in-Figs. 1 and 10a, b, c. This is brought about by setting astern toggle 42, the ahead toggle 35 having previously been tripped, resulting in male jaw on hub of arm 43, Fig. 5, now coming in clutch contact with male jaw 44 on hub of arm |5 so that 40, 42, 43 form now the closed link system operating arm l5. The operation of this astern link system is similar to the ahead link system described above and the picture is similar to Fig. 3 only to the other hand,

operation is repeatedg thegate closing the annular space to let the admitted steam actuate the piston and at afce rtain point opening the annumgrp ce fora short time to let the "pison pass andclosing it again irnmediately"'for the next working cycle; I v

By trippingjtoggle 35 the unity of the above link system is interrupted; any movement of bell crank ii z cannot be transmitted to arm |5, spring l bfpulis it immediately into the vertical. position and the gatednto the neutral one where they reinai'n Tsta'tionary. The'engine will stop,since no stearn isadm'ittetf t6 the piston, and if there should remain sorri'e steam in the annular space that is, toggle 35 is tripped, toggle 42 is set, arm l5 points to the left and spring 16 is on the left. "Working steam is admitted to the engine and at the proper time out off by poppet valve 2| being lifted and opened by forked arm 22 and closed by spring 24. This operation is produced for'both going'ahead or astern by the following mechanism; On main shaft 5'are fixedly mountedrdisk 45 with'cam 46'for going' ahead and disk 41 with cam 48 for going astern. Lever 49 piv-' oted on bedplate I operates link 50 carrying ahead roller. 5| which is in the plane of ahead cam-46and astern roller 52 which is in the plane ofastern cam 48. The other end of link 50 is connected "by rod 54 with arm 21 on shaft 23 whichlat-ter by means of forked arm 22 lifts valve 2|. Bracket 53 has several notches to hold lever 49 in its different positions.

When-running ahead, as shown in Fig. 4, lever 49 is held-in its middle position bringing ahead roller 5| on top of disk 45 to be operated by ahead cam 45'which lifts together with the roller 5| the whole link system 50, 54, 2'! and simultaneously valve 2| admitting steam to the engine. As soon as ahead cam passes roller 5| spring 24 pushes 'down valve 3| together with this link system thus cutting off th steam.

In running-astern lever 49 is brought into its outward position bringing-astern roller 52 on top of disk 4'! 'to-be operated by cam 48 while ahead roller 5| is brought beyond reach of ahead cam 46. The operation of the link system is then the sameas for going ahead.

By putting lever 49 into its inward position both ahead and astern rollers are brought beyond reach. of either cam, spring 24 will keep valve 2| closed and the engine will stop.

It will be noted that by varying the position of lever 49 slightly to right or left of its middle position the steam cut off vcanbe varied also.

In all steam engines .the question of steam leakage. is of great importance for the economic efliciency ofthe engine. In most suggested rotarysteam'. engines this question is not considered at all; in others the prevention of steamleakage is .attempted by. reducing the clearances between the rotatingand adjacent parts to a very close fit which is only a temporary expediem? and quickly destroyed through wear in the bearings, inaccuracies in assembling and other causes.

Inmyimproved rotary steam engine steam tightness is obtained in an entirely novel way, as a matter of fact, is produced by the working steam itself. It, therefore, permits of relatively larger clearances between the internal rotating and adjacent parts, resulting in lower manufacturing costs and easier assembling. The means to obtain these results are illustrated in Fig. 8 showing the clearance gap between gate II and hub 8 of the rotor and in Fig. 9 showing the clearance gap between piston 9 and main cylinder 2.

As shown in Fig. 8 a laminated bundle 55 consisting of a number of thin metal strips of varying width and extending the whole length of gate -II is placed in a suitable groove of the gate obliquely to but not protruding, when straight, beyond its periphery and held in place by retaining bar 56 and necessary number of screws. Over the widest strip the gate is slightly undercut forming a pocket for admitting the working steam. Now, when rotor is running in direction of'arrow there is a higher pressure in the space at the right of bundle 55 containing the working steam than in the space at left which is exposed to the exhaust steam. Or, the steam pressure on top of bundle 55 is greater than on the bottom resulting in the deflection of the laminae until their free ends make contact with the hub 8 of the rotor sealing the clearance gap and pre venting any steam leaking to the exhaust side. When the steam pressure is equalized on both sides the laminae will become straight again and the contact broken.

On piston 9 which is rotatable in both directions two such oblique laminated bundles as 55 would be required which, however, as shown in Fig. 9, can be combined in one bundle of laminae shaped in form of a flat V held by a single retaining bar 58 and necessary number of screws, each branch working independently of the other. sides under the widest lamina forming pockets for the working steam.

Thus, when piston 9 rotates in direction of arrow the left side branch of bundle 5'! which is exposed to the working steam will under the steam pressure deflect and make with its free end contact with main cylinder 2 and seal the clearance gap, while the right side branch being exposed equally on top and bottom to the exhaust steam will remain straight. Similar and suitably formed laminated bundles can be applied on other clearance gaps to prevent leakage there.

In Fig. 6 is shown a cross section of my im proved rotary steam engine having a'rotor with two diametrically opposite pistons. The main cylinder has two also diametrically opposite blisters housing each a gate for each piston similar to Fig. l and the chest has two pipe connections leading steam to each piston. Both gates are interconnected by linkage shown diagrammatically in heavy lines, thus working as a unit and requiring one operating mechanism of the type shown in Fig. 3 for one of the two gates with the exception that disks 3B, 39 require each two diametrically opposite notches 3|. Similarly the steam admitting poppet valve 2| requires only one operating mechanism as shown in Fig. 4 with the exception that disks 45, 4! require each two diametrically opposite cams 46, 58.

This double p ston type of my improved rotary has the advantage of more uniform torque, better balancing of the rotor and most importantly the elimination of piston pressure on the main bearings.

The operation of my improved rotary steam engine on board ship is as follows. When at rest both toggle links 35, G2 are tripped, gate H is in The piston is also undercut on both its neutral position, lever 49 in Ets extreme inward position keeping both rollers 5i, 52 beyond the operation of cams 46, 48; therefore, steam valve 2| is closed and no steam is admitted to the engine.

To start running ahead the ahead toggle l nk 35 is set, lever 49 is brought into its middle position bringing ahead roller 5| in contact with ahead cam 46, valve 2| is lifted admitting steam to the engineand it starts running ahead. Should at the start the ahead cam 46 be in a position away from ahead roller 5| and so valve 2! remain closed, then steam from a small hand operated auxiliary valve is admitted to the engine to start it. as is the usual marine practice.

To reverse the engine, that is, to change from going ahead to going astern the ahead toggle 35 is tripped causing gate H to assume its neutral position, as shown in Fig. 10d, and preventing steam from reaching the piston so that the engine will stop. Then astern toggle 42 is set and lever 49 brought into its outward position bringing astern roller 52 into operation by astern cam 48 and the engine will run astern.

The toggle links 35 and 42 will be interlocked so that they cannot be set at the same time; only one can be set at a time whilethe other remains tripped, however, both can be tripped simultaneously.

All the above described manipulations can through suitable linkage be operated from a central station in the engine room or even may be led to the bridge to be controlled from there.

Figs. 1 to 6 illustrate my improved rotary steam engine wherein the steam is expanded'in a single stage. Since my rotary works on the uniflow princ ple this one stage steam expansion would not aiTect itsefficiency to the same extent as in a reciprocating engine. However, especially for larger units, I prefer to make the steam work in two or more stages. Fig. 7 shows in outline a compound rotary steam engine in which a HP rotary works on the high pressure stage of the steam cycle, exhausting into the valve chest of the larger low pressure rotary working on the low pressure stage of the steam cycle and exhausting into the condenser. Otherwise the construction of both rotaries is the same as described above. Both can be mounted on one shaft as in a single screw ship or onseparate shafts as in twin screw ships.

Although my improved rotary steam engine is intended primarily for use on steamships it also can be used with advantage on land where reversible engines are required, for example, in steel. rolling mills, mining hoists and other plants. In cases where the reversibility is not required the unnecessary parts can be omitted, further simplitying my rotary.

In the above specification and annexed drawings my improved rotary steam engine is shown in its simplest embodiment; however, other modifications and Variations are possible within the spirit and scope of my invention.

I am aware that piston type rotary steam engines have been previously suggested, although never made workable, therefore, I do not claim this type broadly asmy invention. However the peculiar combination of the main working with other assisting elements, though all individually well known, but through novel functioning, creating a practical and eiiicient frotary steam engine is what I can claim as my invention.

I claim: l

1. A rotarysteam engine q of the piston type, comprising a main cylindrical body closed at both ends, a main shaft coaxially located in the main cylindrical body, a rotor hub on said shaft and within said cylindrical body forming with said cylindrical body, a concentric annular space, 'a piston projecting radially from said hub to the inner cylindrical surface of said cylindrical body, a part-cylindrical valve chamber on said cylindrical body extending longitudinally thereof and communicating with said main cylindrical body, the axis of said valve chamber being parallel to the axis'of said cylindrical body, the valve chamber being closed at its opposite ends, ashaft within said valve chamber co-ax altherewith' a roller valve withinsaidvalve chamber and on said last mentioned shaft, means to intermittently and periodically oscillate said roller valve through predetermined angles in timed relaton to the rotation of said piston in one direction, means to render said last means inoperative, said piston being formed with a groove in a surface thereof adjacent an inner surface of said cylindrical body, and a bundle of laminated flexible strips fixed to the piston and projecting into said groove, the outer ends of said strips being in a common plane and normally spaced from the inner surface of saidmain cylindrical body, sad bundle of strips being spaced from the bottom of the groove, whereby steam within the groove is adapted to force the outer ends of said strips against the inner surface of said cylindrical body, to seal the space between the piston and said inner surface. 1

2. A rotary steam engine of the piston type, comprising a main cylindrical body closed at both ends, a main shaft co-axially located in the main cylindrical body, a rotor hub on said shaft and within said cylindrical body formingiwith said cylindrical body, a concentric annular space, a piston projecting radially from said hub to the inner cylindrical surface of said cylindrical'body, a part-cylindrical valve chamber on said cylindrical body extending longitudinally thereof and communicating with said main cylindrical body, the axis of said valve chamber being parallel to the axis of said cylindrical body, the valve chamber being ,closed at its opposite ends, a shaft within said valve chamber co-axial therewith, a roller valve within said valve chamber and on said last mentioned shaft, means to intermittently and periodically oscillate said roller valve through predetermined angles in timed relation to the rotation of said piston in one direction, means to render said last means inoperative, said piston being formed with a groove in a surface thereof adjacent an inner surface of said cylindrical body, and a bundle of laminated flexible strips fixed to the piston and projecting into said groove, the outer ends of said strips being in a common plane and normally spaced from the inner surface of said main cylindrical body, said bundle of strips being spaced from the bottom of the groove, whereby steam within the groove is adapted to force the outer ends of said strips against the inner surface of said cylindrical body, to seal the space between the piston and said inner surface, said strips being of gradually increasing width.

3. A rotary steam engine of the piston type, comprising a main cylindrical body, a main shaft coaxially located in the main cylindrical body, a rotor hub on said shaft and within said cylindrical body forming with said cylindrical body a concentric annular space, two diametrically opposite pistons projecting radially from said hub to the inner cylindrical surface of said cylindriiii) cal body, two diametrically opposite part-cylindrical valve chambers on said cylindrical body extending longitudinally thereof and communieatingwith said main cylindrical body, the axes of said valve chambers being parallel to the axis of said cylindrical body, the valve chambers being closed at their opposite ends, a shaft within each of said valve chambers co-axial therewith, both these shafts being interconnected for simultaneous operation, a roller valve within each of said valve chambers, means to intermittently and periodically oscillate said roller valves through predetermined angles in timed relation to the rotation of said pistons in one direction, meansto render said last means inoperative, said pistons being each formed'with a groove in a surface thereof adjacent an inner surface of said cylindrical body, and a bundle of laminated flexible strips fixed to each piston and projecting into said groove, the outer ends of said strips being in a common and normally spaced from the inner surface of said main cylindrical body, said bundle of strips being spaced from the bottom of the groove, whereby steam within the groove is adapted to force the outer ends of said strips against the inner surface of said cylindrical body to seal the space between the pistons and said inner surface.

4. A rotary steam engine of the piston type, comprising a main cylindrical body, a main shaft coaxiall located in the main cylindrical body, a rotor hub on said shaft and within said cylindrical body forming with said cylindrical body a concentric annular space, two diametrically opposite pistons projecting radially from said hub to the inner cylindrical surface of said cylindrical body, two diametrically opposite part-cylin drical valve chambers on said cylindrical body extending longitudinally thereof and communicating with said main cylindrical body, the axes of said valve chambers being parallel to the axis of said cylindrical body, the valve chambers being closed at their opposite ends, a shaft within each of said valve chambers co-axial therewith,

, both these shafts being interconnected for simultaneous operation, a roller valve within each of said valve chambers, means to intermittently and periodicall oscillate said roller valves through predetermined angles in timed relation to the rotation of said pistons in one direction, means to render said last means inoperative, said pistons being each formed with a groove in a surface.

thereof adjacent an inner surface of said cylindrical body, and a bundle of laminated flexible strips fixed to each piston and projecting into said groove, the outer ends of said strips being in a common and normally spaced from the inner surface of said main cylindrical body, said bundle of strips being spaced from the bottom of the groove, whereby steam within the groove is adapted to force the outer ends of said strips against the inner surface of said cylindrical body to seal the space between the pistons and said inner surface, said strips being of gradually increasing width and disposed at an acute angle to the adjacent surface of inside of said cylindrical body. 7

5. A steam engine of the rotary piston type, comprising a cylinder, a pistonrotatably mounted therein, a valve chamber on said cylinder communicating therewith and co-axial therewith, a valve mounted'for oscillation within said valve chamber, a cam mounted for rotation with the piston and disposed externally of the cylinder, follower means adapted to contact said cam,

ed therein, means to provide a seal between the 10 rotating piston and the inner surface of the cylinder, a valve chamber on said cylinder communicating therewith, a valve mounted for movement within the valve chamber, cam means connected for rotation with the piston and disposed externally of the cylinder, spring means to move ,said valve, a member engaging the cam and adapted to be moved thereby and mechanism interconnecting the valve with the cam engaging member, said mechanism being adapted in one position thereof to connect the valve and cam engaging member for concurrent movement and in another position thereof to permit movement of the valve without movement of the cam engaging means.

A. DAVID ISKOLS. 

